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New sprockets - always mean new chain?

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I understand that chains and sprockets wear as an item. No point in new chain with old sprockets, right. How about new sprockets with old (but still very good) chain?

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Shouldn't be a problem.I swapped out the stock sprockets on my E to gear down for woods riding and tomorrow I'm gearing back up again . Just watch the chain stretch. Red locktite on the countershaft sprocket and nut.

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I'd say no. Of course it all depends on how good the "good" used chain is. In most cases you are better off with new chain on used sprockets than used chain on new sprockets. If the chain is warn at all, the pin to pin pitch is longer than .625 and the new sprockets are right on .625. So the chain is going to make the sprockets fit the chain. With sprocket wear, the "pockets" get sloppy but the pitch is still the same so a new chain is not trying to wear the sprockets as much as the other way around.

Of course best is to replace as a set. How does it happen that you have a good used chain on sprockets that need replacing?

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How does it happen that you have a good used chain on sprockets that need replacing?

Two bikes, one I'm selling, just put new sprockets and O-ring chain on that one. The other bike I just bought - basically brand new but has aluminum rear sprocket and standard non Oring chain which I doubt will last any time. The plan was to take the O-ring chain off of the bike to be sold and replace the stock non-Oring chain on the bike to be kept. What I'm thinking about is in 2 months when the aluminum rear sprocket is gone, will I need to replace the O ring chain too? Should I just replace the aluminum sprocket with steel right now? That's what I'm thinking of doing. 🙂

Hope that makes sense.

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Well, on a dirt bike you can always bend the rules a little. If the chain looks good, use it. The Al sprocket might last longer than you think. I used to get about 2K miles on my KDX using aluminum rears. Life cycle was 2 counters, 1 alum rear and 1 RKO chain - 2000 to 2500 miles.

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I'd say no. Of course it all depends on how good the "good" used chain is. In most cases you are better off with new chain on used sprockets than used chain on new sprockets. If the chain is warn at all, the pin to pin pitch is longer than .625 and the new sprockets are right on .625. So the chain is going to make the sprockets fit the chain. With sprocket wear, the "pockets" get sloppy but the pitch is still the same so a new chain is not trying to wear the sprockets as much as the other way around.

Of course best is to replace as a set. How does it happen that you have a good used chain on sprockets that need replacing?

I agree with that...but I've had the best luck all the way around by changing sprockets and chain at the same time as Noble says... 🙂

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I'm still using my stock chain after changing both sprckets. No noticeable wear on the chain (2K mikes) nor the sprockets. I do my best in cleaning and lubing my chain/sprockets on a regular basis. So far, so good.

Dan

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Wear on a chain must be measured and not "noticed".

If your chain is not elongated past ~ 1.5 - 2% longer than new pitch, it is fine to use on new sprockets.

Once the chain elongates from wear past 2%, it will start to deform the teeth.

The change as a set rule is a rule of thumb that is probably the best suggestion, since most people either don't measure their chain properly, or don't know how.

Inversely...if you keep an eye on your chain and KNOW exactly what percent of growth it's at, you can change the chain out when it approaches the >2% mark and never need to change out the sprockets.

But there again, few do this, hence the change as a set rule of thumb.

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never need to change out the sprockets.

Ummm, right.... 🙂

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((Can you disprove whay I'm saying? Of course not.))

You are right once chain is stretched it will ride high on the teeth and accelerate wear on sprockets, but if there is any sprocket wear installing a new chain will accelerate it's wear even quicker.

Key being , check the wear. Aluminum sprockets are a trash item every chain in addition to CS sprockets. The steel rear sprockets have much higher life and can easily double or tripple the life of an aluminum.

DRZ stock steel rears will do 30,000 easily (on the street) if cared for well. How much longer I'm not sure yet. I matched the stock steel rear to an indentical new one at 14,000 miles, No wear could be seen on the match.

Now the CS sprocket was TOAST

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If you CS sprocket was toast...or ANY sprocket for that matter, then the chain is elongated past specification.

If your chain stays less than 1.5% of it's new length, the sprockets will stay intact and serviceable.

Folks tout the super hard steel rears as the savior of chain drive, but in fact they will mask a chain that has grown past spec and is dangerous to run.

A perfect example of this is when your hard rear sprocket shows no wear, and the CS is worn. This is due to the chain elongation and nothing else.

Also, running the hard rear will accelerate the wear on the chain, and in turn accelerate the wear on the CS. So, you could actually say that the hard rear helped to ruin the CS.

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I ran aluminum rears for 20 years, they are crapola compared the steel rears on longevity, DRZ is first bike since the 70's I've ran steel rears and I'll never go back to aluminum. Cs sprockets(hardened steel) wear cause this diameter is very small and are exposed to alot of engine braking.

I replace chains at the stretch level you mention, but I do not see the no wear situation on cs sprockets and aluminum rears that you are.

The argument steel rears are hard on chains, I disagree cause the they don't wear as quickly aids in reducing chain wear.

Please get a picture of a cs sprocket with 15,000 miles on it, with chains that been replaced at 2% stretch, and show me there's no wear on that cs sprocket.

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Spud,

When the energy of a mis-match of pitch is seen at the hard steel working face, there is no give from the hard steel sprocket. The energy from that mis-match has to go somewhere, if you understand pyhsics, and as a result the energy is transferred back to the chain reels themselves. Resulting in accelerated chain wear. This is fact.

And a CS sprocket does produce some unue stress because of it's size. Engineering data provides that the minimum tooth size for a 50 series chain is 17t, however there are very few bikes that ever use a 17t CS. But, the thing that sees this abnormal energy is the chain itself. Many other variables are involved here, such as proper tension and alignment...and whos to say if these factors were proper?

Again though...if the pitch of the chain doesn't change , the teeth on the CS won't change either. I don't care how many "miles" are on it.

I've been around for few years myself. And I have seen scads of folks who claim they have had bad luck for many years, BUT there are many that do not see this "bad luck", probably due to a more precise maintenance schedule.

Doesn't it stand to reason that if some folks can get great longevity from an aluminum sprocket and others don't, that there has to be a root cause for not seeing the same results?

Back in the 70's, many sprocket mfgs were using 6061 aluminum, which is a substandard grade for bike sprockets. Steel CS sprockets can also be substandard.

But, sub-standard material is simply one of the many variables that can account for "bad luck".

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